FIG. 1 illustrates a conventional single zone (i.e., whole house) forced air heating and cooling system, which typically employs a single central heating and cooling plant 11 with respective conduits 15 and 17 to transfer the heated or cooled air to all the various areas or rooms 10, 18 and 19 serviced. In such systems, a single (main) control thermostat 20 and heating/cooling mode control 22 is typically located in one of the cooled or heated areas or rooms serviced (e.g., room 10) to control the temperature of an entire facility or household 13. In conventional hot water heat systems, boiler and/or water cooler is employed to heat or cool water which is circulated pipes (which would augment or replace conduits 15 and 17) to heat exchangers (not shown) located in various rooms 10, 18 and 18. Like forced air systems, the single (main) thermostat 20 and mode control is typically located in one of the many heated or cooled rooms to automatically control the temperature for the entire facility or household 13.
In the above systems, conduits 15 and 16 transfer the heated or cooled fluid or air to each area or room 10, 18 or 19 serviced. Such systems are limited in that they fail to adequately provide for the automatic, individual temperature control in each of the rooms or areas. For example, dampers 16 are often utilized to alter airflow within the supply conduit 15 to balance the heating and cooling throughout the facility or household 13 to more evenly heat/cool the facility. In an attempt to overcome the limitations of the single zone systems of FIG. 1 and to conserve energy many homes have multiple zone heating and cooling systems, each zone being a subset of the entire facility 13. These systems require the installation of separate heating/cooling plants 11 for each zone. While more efficient than single zone systems, such systems are disadvantageous due to the prohibitively high costs of installing separate heating/cooling plants and conduits or pipes for each zone.
Another disadvantage of conventional single zone systems is that in homes that employ a single main thermostat 20 for all the rooms 10, 18 and 19, all of the rooms are heated or cooled to substantially the same temperature without any provision to control and maintain the individual room temperatures during the period of use or non-use. This condition results in the wasting and excess use of energy. For example, because the facility thermostat 20 is in room 10, it is not possible to raise the temperature of room 18 to 70° F. while maintaining the other rooms 10 and 19 at 60° F. It is not possible to do so as the heating plant 11 will turn-off when room 10 reaches 60° F., which will be before room 18 reaches 70° F. Dampers 16 or room vents (not shown) may be adjusted to divert warm air to room 18, however, this too fails to accurately vary and control the individual room temperatures. Other systems, such as that described in U.S. Pat. No. 6,105,927 to Zelczer et al. disadvantageously require flow control devices that close the fluid flow.
In view of the foregoing, there is a need for a device that will individually control room temperatures in facilities having a conventional heating/cooling plants. There is also a need for a device that reduces energy consumption with minimal compromise in comfort. Further, there is a need for the device to operate in both heating and cooling environments, baseboard heating systems, and forced air systems. Yet further, the device should be relatively cost effective in achieving these needs. The present invention provides such a system.